rb20det developments and problems

Post by **Carl H** » Mon Apr 12, 2004 4:22 pm

have you checked the engine temp ecu sensor?if that goes south then the ecu wont let the engine rev past 5k and you will have absolutely no power.its easy to check its in the r32 engine manual on page EN-382.one from a z32 will work fine, mine was knackerd (so i thought) and i replaced it with this one and it seems to run better.also if you have a vac leak the your idle will be high.

Post by **PROJECTRB240SX** » Mon Apr 12, 2004 4:22 pm

I'LL CHECK THAT.... THANKS.

Post by **PROJECTRB240SX** » Mon Apr 12, 2004 4:22 pm

well guess what? I did and engine running test for codes.... and what flashes code 13! Whats code 13? Water Temp Sensor! I'll be changing this soon and hopefully this fixes my problems.

Post by **JonPowell** » Mon Apr 12, 2004 4:22 pm

Carl is the MAN!!!

Post by **PROJECTRB240SX** » Mon Apr 12, 2004 4:22 pm

I didn't realize that nissan was alot like chevy in which the ecu relies on three main systems for ecu control. CAS (Timing Sensor), MAF (Air Flow Sensor), and ECT (Engine Coolant Temp Sensor). If you have failure in either of these three systems your engine is not going to run worth a ****.

Post by **PROJECTRB240SX** » Mon Apr 12, 2004 4:22 pm

WHICH 300ZX SENSOR DID YOU ORDER?

Post by **BoostFab** » Mon Apr 12, 2004 4:22 pm

good job with debugging.

Post by **PROJECTRB240SX** » Mon Apr 12, 2004 4:22 pm

THE 90-95 SENSOR IS THE SAME AS THE 89-96 240SX SENSOR (WHICH IS WRONG) AND THE 1996 IS THE SAME AS THE 97-98 240SX SENSOR WHICH I DON'T KNOW IF ITS RIGHT.

Post by **PROJECTRB240SX** » Mon Apr 12, 2004 4:22 pm

HOPEFULLY ITS THE PROBLEM.... WELL JUST BY PLAYING WITH IT YESTERDAY I BROUGH THE IDLE DOWN TO 1000RPM INSTEAD OF 1400.

Post by **PROJECTRB240SX** » Mon Apr 12, 2004 4:22 pm

DID YOU HAVE TO USE A 300ZX PIGTAIL FOR THE SENSOR TO WORK?

Post by **PROJECTRB240SX** » Mon Apr 12, 2004 4:22 pm

THE PLUG HEADS FROM THE RB20DET AND THE 1998 240SX (KA24DE) LOOK SIMILAR/THE SAME.... I'LL BE TRYING THIS.

Post by **Carl H** » Mon Apr 12, 2004 4:22 pm

90-96 z32 sensor works.plugs right in, no splicing needed.actualy it seems any v6 temp sensor will work as long it is a newer v6, not the sohc v6's.

Post by **PROJECTRB240SX** » Mon Apr 12, 2004 4:22 pm

UMM ITS NOT THE SAME ON MY CAR. MY PLUG IS OVAL AND THE 300ZX ONE IS SQUARE. THE ONE I HAVE IS LIKE THE 98 KA24DE SENSOR.

Post by **PROJECTRB240SX** » Mon Apr 12, 2004 4:22 pm

It wasn't ECT... I still have the problems.

Post by **GTR Shop** » Mon Apr 12, 2004 4:22 pm

You ahve a inlet leak AFTER the throttle body somewhere.. idel control valve is leaking maybe?Go and 'sqeeze' each hose one by one untill you get a change. listen for hissing etc.Are the oil breathes all hooked up off the rocker cover as per normal, back into the intake?Rbs will run pretty good even with most of the sensors off.. they arn't that reliant on them.Some 25s will start and idle niocely with the AFM disconnected. you can even get a reasonable revout of them!

Post by **Carl H** » Mon Apr 12, 2004 4:22 pm

oh man that is weird.the z32 sensor plugs right in.what year is your engine?mine is a 93.i have a friend with a 89-90 engine and his is the same as mine.thats is really weird.

Post by **PROJECTRB240SX** » Mon Apr 12, 2004 4:22 pm

I have a 1989 240sx w/ a 1990 rb20det

Post by **PROJECTRB240SX** » Mon Apr 12, 2004 4:22 pm

WELL WE HAVE NARROWED IT DOWN TO IGNITION AND FUEL. MY CO-WORKER THINKS I HAVE VARNISH BUILD UP AND A CLOGGED INJECTOR SO THE ENGINE IS KICKING UP THE IDLE TO COMPENSATE. THERE AREA TON OF MISFIRES AND BACKFIRES OUT THE EXHUAST SO I'M THINKING I MAY HAVE IGNITION PROBLEMS BECAUSE OF THE FUEL ISSUES (AKA: FOULED PLUGS, BURNT OUT COIL PACKS, FRIED AMPLIFIER, ETC.).

Post by **PROJECTRB240SX** » Mon Apr 12, 2004 4:22 pm

I'M GOING TO TRY AND SEA FOAM THE ENGINE AND SEE WHAT HAPPENS.

Post by **eh?** » Mon Apr 12, 2004 4:22 pm

I'm sorry man but your going off in the wrong directions. I know you're probably getting impantient and would like to drive the car off a cliff. If the car was in perfect order before you installed the FMIC something must have gone wrong with the installation. All you have listed (high idle,misfires, unable to rev beyond 5k, ecu code 55) point to a vacuum leak. If you've checked everything and cannot find a leak, I would reinstall the SMIC with original piping in the original configuration. If it runs the same then find the highest cliff you can find..

Post by **PROJECTRB240SX** » Mon Apr 12, 2004 4:22 pm

YEAH OK THERE ARE 5 VACUUM LINES ON THE CAR AND THEY ARE ALL PERFECT I EVEN CHANGED THEM, WE THEN CHECKED FOR AIR LEAKS AND THERE WERE NONE. I NEVER HAD THE SMIC IT HAS ALWASY BEEN FMIC, THERE ARE NO AIR LEAKS FROM THE FMIC OR SETUP.

WHAT I'M DOING IS ANOTHER ATTEMPT AND EVEN IF IT DOESN'T WORK AT LEAST IT WAS TRIED AND IT'LL HAVE ALL NEW PLUGS, O2 ANDA NICE CLEAN ENGINE.

Post by **eh?** » Mon Apr 12, 2004 4:22 pm

So what exactly did you remove to install the new fmic?

Post by **PROJECTRB240SX** » Mon Apr 12, 2004 4:22 pm

the old fmic piping and ic.

Post by **HybridOne** » Mon Apr 12, 2004 4:22 pm

My RB idles at 1800-1900rpms. And i'm starting to have problems around 5k rpm...the car pulls strong until then and then it just kind of drops out. I'm changing the O2 today. All my plugs are fine. Though...i'm not getting any sort of reading on my air/fuel gauge. I have it wired to my O2 and it doesn't even light up at all. I've checked vacum at least 20 times. I replaced the AAC and the Air regulator. I've tested resistance and voltage on the temp sensor. I replaced the MAF. I switched out my coilpacks. I have no idea what is going on. And i have the FSM, but it doesn't tell me how to pull codes from the ECU.....how are you guys pulling codes? and what do they mean? (what do the numbers corrispond to?)

I'm in the same boat as you project.

Post by **xjon** » Mon Apr 12, 2004 4:22 pm

I believe you can pull codes the same way you do with the KA ecu's which is on the back side of the ecu is a dial (use screwdriver) and also a red lamp which blinks you the codes. Read the number of times it blinks (fast and slow) and that is your number. Then check your FSM. Sorry not so detailed but if you need more details just ask.

Also I believe that some Ecu's dont have the lamp even. That case, I don't know.

Post by **PROJECTRB240SX** » Mon Apr 12, 2004 4:22 pm

THANK GOD ITS NOT ONLY ME! EVEN THOUGH IT REALLY SUCKS.

TO PULL CODES:1.) TURN KEY TO ON2.) TURN ECU DIAL FULL CCW3.) COUNT FLASHES (FIRST NUMBER IS SLOW, SECOND NUMBER IS QUICK)4.) CODES AUTO CLEAR ONCE ITS TURN FULL CW AND POWER IS CYCLED.

MY CAR IS IDLING BETTER AND RUNNING ALOT SMOOTHER NOW THAT I DID THE SEA FOAM CLEANING BUT ITS NOT IDLING LOW ENOUGH AND BECAUSE I LOST MY BRAKES YESTERDAY I DIDN'T GET TO TEST THE LIMITER THINGY OUT.

Post by **HybridOne** » Mon Apr 12, 2004 4:22 pm

i am changing my O2 right now...well not right now, but in a minute. I will let you know what happens. Thanks for the info on how to check codes....but what do they mean? Where is a listing of the codes?

Post by **eh?** » Mon Apr 12, 2004 4:22 pm

http://www.rb25det.org/error.htm

Post by **GTR Shop** » Mon Apr 12, 2004 4:22 pm

PROJECT: You problem is 'AIR'

You vacuum is too low.The prob is between the throttle body and the head.

Remove all the vacuum lines and replace with 1" long pieces with bolts in the end, if that make no diff,leave them there and look at the throttle body itself.Is it against the stop?Slack in throttle cable?Does the engine only run high with the bonnnet down?With the pipe off, can you see it shut?Next thing to do is to put a set of vicegrips on t he airhose under the lower plenum. (clamp it off)ANy change?If not then stick the grips (but not as tight) on the rubber supply line to inj rail.. any diff?If not, then try the return line.

*Always fault find with the 02 unplugged*Are you uing the std fuel pump?DO you have good block ground?Is the ignitor grounded?Have you had the intake emanifold off since you've had the engine?Have you had to cut any of the wiring loom?What voltage are you seeing at idle on the AFM.. what about when you give it a rev?

Give me some answers to the above and we'll go from there

Post by **HybridOne** » Mon Apr 12, 2004 4:22 pm

code 34. Knock sensor signal system. only code i've thrown thus far. I just replaced the O2, i'm gonna reset the ecu and then test drive the car. Thanks for the info.

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